We plan to utilize our in vitro reconstitution system to define the functions and interrelationships of the 3 nucleocapsid proteins of vesicular stomatitis virus during transcription. Since transcription and replication are apparently interrelated, these studies will form the foundation for projected studies on how RNA replication occurs at the molecular level. Various ts mutants from different complementation groups will be characterized to determine which of the three nucleocapsid proteins contains the ts lesion in each group.